This invention relates to preparation of propranolol hydrochloride macrocrystals and more particularly to the preparation of high yields of propranolol hydrochloride macrocrystals having a particle size within the range of 420 to 1200 microns. The propranolol hydrochloride macrocrystals are useful in pharmaceutical capsule dosage forms, either uncoated, or coated to provide delayed or sustained release therapeutic preparations.
Propranolol hydrochloride is a well known pharmaceutical which has heretofore been marketed in tablet form and as sustained release encapsulated spheroids. See, for example, U.S. Pat. Nos. 3,337,628 and 4,138,475. In these pharmaceutical preparations, propranolol hydrochloride in powder form is utilized to form the tablets and spheroids. The propranolol hydrochloride is crystallized from solvents such as cyclohexane under conditions to provide crystalline material in the size range of 10 to 50 microns mean particle size depending on grade.
In forming tablets of propranolol hydrochloride powder, it is conventional to admix the active ingredient with excipients such that a small but accurate amount of active ingredient, i.e. 10 or 20 milligrams, may be slugged and formed into tablets weighing of the order of 105 to 120 milligrams.
Also in forming spheroids in accordance with U.S. Pat. No. 4,138,475 the propranolol hydrochloride powder is admixed with microcrystalline cellulose in order to form spheroids which are then film coated to provide sustained release dosage forms.